Detection of microemboli by constant-pressure filtration during in vitro circulation of bovine and human blood.
The constant-pressure filtration (CPF) method has been developed to assess blood microemboli (BME) in terms of their ability to occlude microvascular flow. Previous reports suggest that the method is sensitive to the effects of platelet stimulation and to blood-pumping conditions. BME production and heparin activity were studied in bovine and human blood pumped by a Pellethane ventricle with Pellethane molded valves connected via smooth quick-connects to a Pellethane horseshoe-shaped reservoir. In each experiment, blood was collected into heparin by cardiac puncture from a stunned animal or by venepuncture from a human donor. The blood from each donor was filled into three ventricle-reservoir systems (50 cc ventricle and 1,500 cc reservoir for the bovine blood, and 20 cc ventricle and 150 cc reservoir for the human blood). One of the systems received aspirin (ASA; 25 mg/dl) shortly after the onset of pumping, whereas the other two served as pumping and non-pumping controls. The blood was pumped in a full-fill/full-eject mode for up to 10 h. BME concentration was measured by the CPF method in which the blood was filtered through 20-microns pore filters at 20 mm Hg for 10 s, and the flowrate curves were evaluated from occlusion model. Heparin activity was measured by the activated partial thromboplastin time (APTT) test. In the early period after the onset of pumping, the BME concentration increased, whereas the APTT decreased from an initial value of greater than 250 s, with the relative rate of change for both the BME and the APTT being the following: pumping control greater than pumping ASA blood greater than quiescent control.(ABSTRACT TRUNCATED AT 250 WORDS)
Solen
K A
KA
Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602.
Mohammad
S F
SF
Pijl
A J
AJ
Swier
P
P
Monson
R D
RD
Olsen
D B
DB
D000818:Animals; D001241:Aspirin / Q000494:pharmacology; D002417:Cattle; D004617:Embolism / Q000097:blood*; D005374:Filtration / Q000379:methods*; D006353:Heart-Assist Devices; D006493:Heparin / Q000097:blood; D066298:In Vitro Techniques
D006493:Heparin; D001241:Aspirin